"YouTube censorship" blocks historical information in favor of not offending the most PC class (apart from Muslims).
Go to 9:22 point: https://www.youtube.com/watch?v=V7TKkYTeg0A
And that is what the narrator actually has to say (with a clearing of the throat).
NegerschweiB: It translates as, "Negro sweat," according to some online translations.
